JPH045206B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of controlling an unmanned vehicle to travel from a starting point to a destination point and to stop the vehicle at the destination point.

Various methods have been proposed and put into practical use to allow vehicles to travel unmanned along travel paths constructed of optical reflective chips or the like on the factory floor without using rails.
A conventional travel control method of this type is performed as shown in FIG. 1, for example. FIG. 1 is a schematic plan view showing a conventional driving control mode of an unmanned vehicle, in which an optical reflective tape R is pasted on the floor in a loop connecting the starting point O and the destination points A, B, etc. A travel route is constructed using the same method, and a large number of count marks CM made of optical reflective tape or the like are also pasted at regular intervals along this travel route. On the other hand, the unmanned vehicle 30 is equipped with sensors 31 and 32 that detect the optical reflective tape R for the traveling route and the count mark CM, respectively.
While running the automatic guided vehicle 30, the sensor 32 counts the count marks CM, and each time this count reaches the number of count marks from the starting point O to each destination point A, B, etc., the automatic guided vehicle 30 is braked. The vehicle is then selectively stopped at each destination point A, B, etc.

However, with this control method, if there is a falling object similar to a count mark in the middle of the driving route, or if the count mark is dirty, the count to the destination point will deviate, and if the vehicle meandering along the way, etc. Similarly, if you make a mistake in counting the count marks, the machine will stop at a position far from the destination point, and since the errors accumulate, the positional deviation will increase as the distance traveled increases, and the number of count marks will also increase. There were some problems, such as it was not easy.

The present invention has been made in view of the above circumstances, and its purpose is to provide a station mark at each destination point, and use at least three sensors mounted on an unmanned vehicle to mark this station mark. By determining the number of station marks detected by these sensors by majority vote and allowing the vehicle to travel while correcting the detection errors, it is possible to reduce as much as possible errors in the stopping position due to errors in station mark detection, and to prevent the vehicle from traveling. To provide a travel control method for an unmanned vehicle that does not accumulate errors even when the distance becomes long and can accurately stop at each destination point.

A driving control method for an unmanned vehicle according to the present invention is a driving control method for sequentially driving an unmanned vehicle along a driving route from a starting point to a plurality of points and stopping at a predetermined point. A mark placed at a location is detected by at least three sensors installed on an unmanned vehicle, and among the number of marks detected by each sensor, the number of detected marks with the highest number of matches is determined as a reference value using majority voting logic. , the number of marks detected by the sensor whose number of marks detected does not match the reference value is corrected to the reference value, and when this reference value matches the predetermined value, the unmanned vehicle is placed at the point where the mark is placed. It is characterized by stopping.

The method of the present invention will be specifically explained below based on the drawings showing its implementation state. FIG. 2 is a schematic plan view of the ground equipment used to carry out the method of the present invention, and R in the figure is an optical reflective tape for setting the travel route, SMa,
SMb...SMe indicates a station mark provided for each station, which is each destination point, and 1 indicates an automated guided vehicle (hereinafter simply referred to as a traveling vehicle). The travel route is set by pasting an optical reflective tape R on the floor so as to form a loop connecting the starting point O and the destination points A, B, . . . . Note that this travel route setting means is not limited to the case where an optical reflective tape is used, and any conventionally known means such as a magnetic tape may be used as appropriate. Furthermore, it goes without saying that the travel route is not limited to a loop-like configuration, and may simply be configured to connect the starting point and each destination point in a straight line.

Station marks SMa, SMb, …SMe and
SMo is also constructed using optical reflective tape, and an optical reflective tape that is equal to or longer than the vehicle width of the traveling vehicle 1 is placed at the starting point O and each destination point A, B, etc. in the longitudinal direction. It is attached to the floor surface with the center part perpendicular to the travel route. Station marks SMa and the like are pasted onto the optical reflective tape R for setting the running route to prevent the optical reflective tape R from peeling off. The traveling vehicle 1 travels in the direction of the arrow from the starting point O along the travel route, stops selectively at each destination point A, B, and so on, and repeats the process of returning to the starting point O.

FIG. 3 is a schematic plan view of the traveling vehicle 1, and FIG. 4 is a block diagram of the traveling control system.
12 is a front wheel, and 13l and 13r are rear wheels. The front wheels 12 are pivotally supported by a caster frame rotatably supported around a vertical axis provided at the lower center of the front part of the vehicle body 11, and the rear wheels 13l and 13r are located near the rear of the vehicle body 11 and are located on the left side. , are pivotally supported on both right sides using bearings 13a, 13a, respectively. Toothed pulleys 13b, 13b are integrally provided on each of the rear wheels 13l, 13r coaxially with the rear wheels 13l, 13r, and each toothed pulley 13b, 13b is operated separately on the left and right sides using toothed belts 13c, 13c, respectively. It is connected to toothed pulleys 14a, 14a provided on the output shafts of motors 14l, 14r with reduction gears.
16 is a control section for the motors 14l and 14r, 17 is an arithmetic control section for the traveling vehicle 1, and 18 is a battery.
On the other hand, on the lower surface of the vehicle body 11, there is a traveling sensor _S1 located in front of the front wheels 12 to trace the optical reflective tape R for the traveling route, and station marks are located approximately at the center of the front and rear of the vehicle body 11. SMa,
A sensor S ₂ for detecting SMb, etc. and performing deceleration control further has station marks SMa, SMb, etc. on the left and right side edges of the vehicle body 11 corresponding to the axle ends of the left and right rear wheels 13l, 13r. There are sensors S ₃ l, S ₃ r for detecting such things and stopping the vehicle 1, and bumper sensors SS ₄ at the front and rear of the vehicle body 11 for stopping the vehicle 1 when it collides with an obstacle. l,
S ₄ r are installed respectively.

The steering sensor _S1 is composed of light-receiving elements that detect the reflected light from the optical reflective tape R and are arranged in parallel in the width direction at the center of the lower surface of the vehicle body 11. The signal is output to the motor control section 16, and the control section 16 controls the motor 14 in order to eliminate the positional deviation of the widthwise center of the vehicle body 11 with respect to the widthwise center of the optical reflective tape R.
It is designed to control the rotational speed of the motors 1 and 14r. The sensor S ₂ for starting deceleration control is also composed of a light-receiving element, etc., and when it detects a station mark SMa etc., it outputs a signal to the calculation control unit 17 and the signal is sent to the calculation control unit 17 via the control unit 16. A deceleration control signal is output to the motors 14l and 14r. The sensors S ₃ l and S ₃ r are similarly composed of light receiving elements, etc., and when they detect the station marks SMa, SMb, etc., they output the detection signals to the calculation control section 17, and via the control section 16 they output the detection signals to the motor 14 l. , 14r, and the arithmetic control unit 17 causes the brakes 19l, 14r to stop.
A signal is output to 19r to stop the rear wheels 13l and 13r. Bumper sensor S ₄ l,
S ₄ r is composed of switches etc., and is located in front of the vehicle body 11.
It is attached to the bumpers 11a and 11b provided at the rear, and is normally off, but turns on when it collides with an obstacle, outputs a signal to the arithmetic control section 17, and controls the arithmetic and control section 17 to turn on the control section 16. The power supply to the motors 14l, 14r is stopped through the brakes 14l, 14r, and a control signal is output to each of them to directly operate the brakes 19l, 19r.

Reference numeral 20 denotes a manual operation unit, which is used to switch between manual mode and automatic mode when driving the vehicle 1, or to switch from the starting point O to each destination point A, B, C, etc.
Station mark SMa that must be passed when reaching .
The number of SMb..., for example, to reach destination A,
1 except for station mark SMo at starting point O
When reaching the destination point C, the counters associated with the three sensors S ₂ , S ₃ l, and S ₃ r
Set numerical values in N ₁ , N ₃ , and N ₄ .

Next, the travel control process according to the method of the present invention as described above will be explained with reference to the flowcharts shown in FIGS. 5-7. First, the starting point O is selected through the manual operation section 20.
Enter the number of station marks SMa, etc. (3 in Fig. 2) that you will pass on the way to a specific target point, for example C, and direct the vehicle 1 to the destination point on the starting point O on the traveling route. Turn on the mode changeover switch on the operation unit 20 to the automatic mode side, and press the start button. As a result, the motors 14l and 14r rotate at low speed,
The traveling vehicle 1 starts traveling at a low speed (step).
After a predetermined time (T seconds) has passed after the start of driving, each sensor
Put S ₂ , S ₃ l, and S ₃ r into operation (step),
Furthermore, an interrupt is permitted (step), and a control signal is output from the arithmetic control section 17 to the control section 16 to accelerate the motors 14l and 14r, so that the vehicle 1 runs at a constant speed at a predetermined speed. Move to (step). Next, after going through a subroutine (step) as shown in Fig. 6, it is determined again in the main routine whether or not the arrival flag is set (step), and if YES, the control is terminated, and if NO In this case, the process of the subroutine described above will be repeated. In this process, the sensor S ₂ for starting deceleration control or the destination coincidence detection sensor
When either S ₃ l or S ₃ r detects station mark SMa or the like, an interrupt process of a subroutine as shown in FIG. 7 is performed. That is, until the vehicle 1 reaches the destination point C from the starting point O in FIG. 2, the station mark SMo at the starting point O is removed (a time delay is provided so that the sensors _S3r and S3l do not operate near the starting point. ) will pass through three station marks, but as mentioned above, the sensor
One of S ₂ , S ₃ l, and S ₃ r detects the station mark (when the vehicle 1 is in a normal running state, sensor S ₂ detects the station mark first, then S ₃ l detects the station mark). , S ₃ r will detect the station mark almost at the same time, but the sensor S Prior to _{step 2} , the sensors S ₃ l and S ₃ r may detect the station mark at the same time, or either one of them may detect the station mark.) Then, the interrupt processing of the subroutine shown in FIG. 7 is performed. First, it is determined whether the sensor S ₂ for starting deceleration control has detected the station mark (step), and if NO, it is determined whether the sensor S ₃ l for stop control has detected the station mark. (Step), and if NO, it is determined whether another sensor _S3r has detected the station mark (Step). When sensor S ₂ detects the station mark, i.e. YES
In this case, the set number n ₁ of the counter N ₁ associated with this sensor S ₂ (when the destination point is C, the set number is 3) is counted down by 1 (step 11a), and then the set number n 1 is counted down by 1 (step 11a). is zero (step 11b), and if NO, return; if YES, the arithmetic control section 17 outputs a control signal to the control section 16 to control the deceleration of the motors 14l and 14r. Shift to deceleration driving (step 11c) and return. In addition, when the stop control sensor S ₃ l detects a station mark, the counter N ₃ associated with the sensor S ₃ l is set number n ₃ (when the destination point is C, the set number is 3). ) is counted down by 1 (step 12a), a detection flag is set (step 12b), and when the stop control sensor S ₃ r detects the station mark, the counter N ₄ associated with the sensor S ₃ r is counted down. The set number _n4 is counted down by 1 (step 13a), a detection flag is set (step 13b), and the process returns.

On the other hand, in the step, the sensors S ₂ , S ₃ l, S ₃ r
If the number of station marks detected by at least two sensors is equal among the respective number of station mark detections, this is determined to be the correct number of station marks, that is, the reference value, and the station mark detection of the other one sensor is determined. If the number is different from this, the operation is repeated to correct the number of detections and make the number of station mark detections of the three sensors coincide each time one of the sensors S ₃ l and S ₃ r detects a station mark. That is _, first, the detection flag is set ( _step
12b, 13b), (step 5a),
If YES, the number of sets n ₁ in the counter N ₁ related to sensor S ₂ and the counter N ₃ related to sensor S ₃ l
It is determined whether the number of sets in counter _N3 of sensor S3l is equal or not (step 5b), and if YES, after delaying the time by about 0.2 to 0.3 seconds (step 5c), the number of sets in counter _N3 of sensor _S3l is Determine whether or not n ₃ is equal to the number of sets n ₄ in counter N ₄ related to sensor S ₃ r (step 5d). If YES, continue as is.
If NO, after correcting the number of sets n ₄ of counter N ₄ to the number n ₁ of sets of counter N ₁ (step
5e), reset the detection flag (step
5f).

The delay time in step 5c is as follows:
If the traveling direction of the is inclined with respect to the traveling route, the time required from either sensor S ₃ l or S ₃ r to detect the station mark after the other sensor detects the station mark is This absorbs the difference in the station mark detection time of each of the sensors S ₃ l and S ₃ r.

On the other hand, when it is determined whether the set numbers n ₁ and n ₃ of counters N ₁ and N ₃ are equal (step 5b), NO
In this case, the number of sets of counters N ₁ and N ₄ is n ₁ , n ₄
are equal (step 5g), and if YES, after delaying the time by about 0.2 to 0.3 seconds (step 5h), the set values at counters N ₃ and N ₄ of sensors S ₃ l and S ₃ r are determined. Determine whether the numbers n ₃ and n ₄ are equal (step 5i), and if YES, leave as is, or leave NO.
In the case of , set number n ₃ of counter N ₃ is set to counter N ₁
After correcting the set number n to ₁ (step 5j), the detection flag is reset (step 5f). Furthermore, when it is determined whether the set numbers n ₁ and n ₄ of the counters N ₁ and N ₄ are equal (step 5g), if NO, that is, the numbers n ₁ and n ₄ of the counters N 1 and N ₄ are equal. If the number of station marks detected is different, after delaying the time by about 0.2 to 0.3 seconds (step 5k), the counter
It is determined whether the set numbers n ₃ and n ₄ of N ₃ and N ₄ are equal (step 5l), and if YES, the counter N _{3 is}
Determine whether the set number _n3 of is zero (step 5n),
If YES, reset the detection flag (step 5f); if NO, determine whether the set number of counter _N1 is zero (step 5n); if NO, leave it as is; if YES, leave it as is. After returning to constant speed running (step 5o), the number set in counter _N1 is corrected to the number _n3 set in counter _N3 , and the detection flag is reset (step 5f).

Next, it is determined whether the set number of counter _N3 is zero (step 5q), and if NO, continue as is.
If YES, the arithmetic control unit 17 issues a control signal to the control unit 16 to stop the power supply to the motors 14l, 14r, and directly brakes 1
Output a braking signal to 9l and 19r (step 5r),
The arrival flag is set (step 5s) and the process returns to the steps of the main routine shown in FIG.

Note that when it is determined in step 5l whether the set numbers n ₃ and n ₄ of counters N ₃ and N ₄ are equal,
If NO, in other words the sensors S ₂ , S ₃ l, S ₃ r
If the numbers of detected station marks are different, abnormality processing such as stopping the traveling vehicle 1 is performed (step 5t), an abnormality flag is set (step 5u), and the process returns to the steps of the main routine.

Therefore, each time one of _the three sensors S ₂ , S ₃ l, S ₃ r detects a station mark, _each sensor S ₂ , S ₃ l , S ₃ r detects a station mark, the number of station marks detected by each sensor S ₂ , S ₃ l, and S ₃ r is compared, and the detected numbers match by majority logic. The process of correcting the number of detections from the mismatched sensors to the reference value is set as the reference value, and the process of correcting the number of detections from the mismatched sensors to the reference value is repeated each time the station mark is passed. Stop.

Furthermore, if the numbers of detection station marks of each sensor S ₂ , S ₃ l, and S ₃ r are all different, an emergency stop will occur as an abnormality, and no runaway will occur.

Although the above embodiment shows a configuration in which three sensors are used, the configuration is not limited to this.
Any number is acceptable as long as it is more than one.

As described above, in the method of the present invention, a mark placed at a target point is detected by three or more sensors installed on a traveling vehicle, the number of detections is determined as a reference value by majority logic, and other Since the number of marks detected by the sensor is made to match this, it is possible to detect the target point more accurately, and since the number of marks detected by other sensors is corrected to the reference value each time, there is no accumulation of errors. The present invention has excellent effects, such as being able to travel long distances, accurately reaching a destination, and stopping at that location.

[Brief explanation of drawings]

Fig. 1 is a schematic plan view showing the control mode of the conventional method, Fig. 2 is a schematic plan view showing the implementation state of the method of the present invention, Fig. 3 is a schematic plan view of the traveling vehicle, and Fig. 4 is the driving control. The system block diagrams, Figures 5, 6, and 7 are flowcharts showing the control procedure of the method of the present invention. 1...Unmanned vehicle, 11...Vehicle body, 12...Front wheel, 13l, 13r...Rear wheel, 14l, 14r...
...Motor, 16...Control unit, 17...Calculation control unit, 19l, 19r...Brake, 20...Manual control unit, R...Optical reflective tape, SMa,
SMb...Station mark.

Claims (1)

[Claims] 1. In a driving control method for driving an unmanned vehicle sequentially along a driving route from a starting point to a plurality of points and stopping at a predetermined point,
The marks placed at each of the above points are detected by at least three sensors installed on the unmanned vehicle, and among the number of marks detected by each sensor, the number of detected marks with the highest number of matches is determined as a reference value based on the theory of majority voting. The number of marks detected by sensors whose number of detected marks does not match the standard value is corrected to the standard value, and when this standard value reaches the predetermined value, the point where the mark is placed is unmanned. A travel control method characterized by stopping a traveling vehicle.